﻿using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using Microsoft.Extensions.Caching.Memory;

namespace XjjXmm.FrameWork.Cache
{
    /// <summary>
    /// 本地缓存
    /// </summary>
    public class XjjxmmMemoryCache : ICache
    {
        private static readonly MemoryCache Cache = new MemoryCache(new MemoryCacheOptions());

        //public DoCareCache()
        //{
        //    // Cache = cache;
        //}

        /// <summary>
        /// 验证缓存项是否存在
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <returns></returns>
        public bool Exists(string key)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));
            return Cache.TryGetValue(key, out _);
        }

        /// <summary>
        /// 添加缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <param name="value">缓存Value</param>
        /// <param name="expiresSliding">滑动过期时长（如果在过期时间内有操作，则以当前时间点延长过期时间）</param>
        /// <param name="expiressAbsoulte">绝对过期时长</param>
        /// <returns></returns>
        //public bool Set(string key, object value, TimeSpan expiresSliding, TimeSpan expiressAbsoulte)
        //{
        //    if (key == null)
        //        throw new ArgumentNullException(nameof(key));
        //    if (value == null)
        //        throw new ArgumentNullException(nameof(value));

        //    Cache.Set(key, value,
        //        new MemoryCacheEntryOptions().SetSlidingExpiration(expiresSliding)
        //            .SetAbsoluteExpiration(expiressAbsoulte));
        //    return Exists(key);
        //}

        /// <summary>
        /// 添加缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <param name="value">缓存Value</param>
        /// <param name="expiresIn">缓存时长</param>
        /// <param name="isSliding">是否滑动过期（如果在过期时间内有操作，则以当前时间点延长过期时间）</param>
        /// <returns></returns>
        public bool Set(string key, object value, TimeSpan expiresIn, bool isSliding = false)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));
            if (value == null)
                throw new ArgumentNullException(nameof(value));
            
            Cache.Set(key, value,
                isSliding
                    ? new MemoryCacheEntryOptions().SetSlidingExpiration(expiresIn)
                    : new MemoryCacheEntryOptions().SetAbsoluteExpiration(expiresIn));

            return Exists(key);
        }

        public bool Set(string key, object value)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));
            if (value == null)
                throw new ArgumentNullException(nameof(value));

            Set(key, value, TimeSpan.FromDays(1), true);

            return Exists(key);
        }

        #region 删除缓存



        /// <summary>
        /// 删除缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <returns></returns>
        public void Remove(string key)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));

            Cache.Remove(key);
        }

        /// <summary>
        /// 批量删除缓存
        /// </summary>
        /// <returns></returns>
        public void RemoveAll(IEnumerable<string> keys)
        {
            if (keys == null)
                throw new ArgumentNullException(nameof(keys));

            keys.ToList().ForEach(item => Cache.Remove(item));
        }

        public void Clear()
        {
            var l = Keys();
            foreach (var s in l)
            {
                Remove(s);
            }
        }



        #endregion

        #region 获取缓存

        public bool Contain(string key)
        {
            return Keys().FirstOrDefault(t => t == key) != null;
        }
        public IDictionary<string, object> GetAll()
        {
            return GetAll(Keys().ToList());
        }

        public long Size()
        {
            throw new NotImplementedException();
        }

        /// <summary>
        /// 获取缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <returns></returns>
        public T Get<T>(string key)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));

            return Cache.Get<T>(key);
        }

        /// <summary>
        /// 获取缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <returns></returns>
        public T GetOnce<T>(string key)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));

            var tmp = Cache.Get<T>(key);
            Remove(key);

            return tmp;
        }

        /// <summary>
        /// 获取缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <returns></returns>
        //public object Get(string key)
        //{
        //    if (key == null)
        //        throw new ArgumentNullException(nameof(key));

        //    return Cache.Get(key);
        //}

        /// <summary>
        /// 获取缓存集合
        /// </summary>
        /// <param name="keys">缓存Key集合</param>
        /// <returns></returns>
        private IDictionary<string, object> GetAll(IEnumerable<string> keys)
        {
            if (keys == null)
                throw new ArgumentNullException(nameof(keys));

            var dict = new Dictionary<string, object>();
            keys.ToList().ForEach(item => dict.Add(item, Cache.Get(item)));
            return dict;
        }
        #endregion



        ///// <summary>
        ///// 删除匹配到的缓存
        ///// </summary>
        ///// <param name="pattern"></param>
        ///// <returns></returns>
        //public void RemoveCacheRegex(string pattern)
        //{
        //    IList<string> l = SearchCacheRegex(pattern);
        //    foreach (var s in l)
        //    {
        //        Remove(s);
        //    }
        //}

        ///// <summary>
        ///// 搜索 匹配到的缓存
        ///// </summary>
        ///// <param name="pattern"></param>
        ///// <returns></returns>
        //public IList<string> SearchCacheRegex(string pattern)
        //{
        //    var cacheKeys = GetCacheKeys();
        //    var l = cacheKeys.Where(k => Regex.IsMatch(k, pattern)).ToList();
        //    return l.AsReadOnly();
        //}

        /// <summary>
        /// 获取所有缓存键
        /// </summary>
        /// <returns></returns>
        public List<string> Keys()
        {
            const BindingFlags flags = BindingFlags.Instance | BindingFlags.NonPublic;
            var entries = Cache.GetType().GetField("_entries", flags).GetValue(Cache);
            var cacheItems = entries as IDictionary;
            var keys = new List<string>();
            if (cacheItems == null) return keys;
            foreach (DictionaryEntry cacheItem in cacheItems)
            {
                keys.Add(cacheItem.Key.ToString());
            }
            return keys;
        }
    }
}

